In the medical practice of “surgery” where the risk of infection is high, there is no method for preventing infections 100%, and surgical site infections (SSIs) occur in 2% to 5%.
In order to reduce surgical site infections (SSIs), it is necessary to pay attention to surgery as a whole, such as complications of the patient, disinfection, the operating theater environment, disinfection/infection management for medical practitioners, and the like. Surgery is usually performed under aseptic conditions, and sufficient consideration is given to hygiene in all situations in medical settings; however, the occurrence rate of surgical site infections (SSIs) differs depending on the type of surgery and the site on which surgery is to be performed. This is due to the degree of difficulty of the process of sterilizing (disinfecting) the site.
For example, in catheter surgery in which a catheter is placed (indwelled) in a blood vessel or ureter, the occurrence rate of surgical site infections (SSIs) exceeds 10% (JANIS, SSI Department, Public Information, July to December 2013 Semiannual Report). The reason for this is because it is not possible to directly sterilize such surgical sites, and because there is currently no method other than to thoroughly sterilize the catheter to be inserted.
Recovery being delayed due to a surgical site infection (SSI) causes an increase in the hospitalization period and medical costs, ultimately resulting in a burden being placed on the patient. Hospitalization periods extend by 15 to 18 days on average, and hospital expenses increase by an average of approximately 450,000 to 540,000 yen per case.
The number of incidences of surgical site infections (SSIs) in Japan is 5,374 cases (JANIS, SSI Department, Public Information, July to December 2013 Semiannual Report), which calculates to additional medical expenses of approximately 4.8 billion yen each year due to the occurrence of surgical site infections (SSIs). Furthermore, the psychological burden on patients faced with the situation of an increased financial burden due to not being able to leave the hospital for a while after surgery cannot be overlooked. Therefore, the development of a technique capable of reducing the occurrence rate of surgical site infections (SSIs) is desired.
Regarding such a technique, PTL 1 discloses a technique for sterilizing a surgical site using an ultraviolet lamp. According to PTL 1, it is possible to sterilize an area including a surgical site by radiating ultraviolet rays using an ultraviolet lamp. Additionally, by radiating visible light rays together with ultraviolet rays, the irradiation range of the ultraviolet rays is visualized.
Furthermore, PTL 2 discloses a sterilizing apparatus provided with: an ultraviolet lamp that emits ultraviolet rays of a wavelength range of approximately 190 nm to 230 nm; and a spectrum filter element such as multilayer dielectric filter or a chemical filter that substantially prevents the inclusion of light outside of the aforementioned wavelength range in the ultraviolet rays. According to PTL 2, it is possible to sterilize microbial bacteria without harming human body cells.
Furthermore, NPL 1 discloses a sterilization technique by means of a Kr—Br excimer lamp of a peak wavelength of 207 nm, in which light of a wavelength of 210 nm or more is removed with a filter. According to NPL 1, it is possible to sterilize microbial bacteria while suppressing harm to human body cells and the occurrence of mutation in skin cells.
Furthermore, PTL 3 describes a method for treating periodontal disease in which ultraviolet rays are guided from an ultraviolet ray light source by means of an optical fiber and radiated onto an affected area. According to PTL 3, it is possible to sterilize periodontal pathogenic bacteria by attaching an optical fiber to the tip end of an instrument or the like used by dentists.